The amino-terminal pro-C-type natriuretic peptide(NT-proCNP)is a diagnostic inflam-matory marker clinically used for diagnosing bacterial infections.This study aims to establish a phage display library of single-chain variable fragment(scFv)antibodies against canine NT-proC-NP and to screen for scFvs with high binding affinity to NT-proCNP.Initially,NT-proCNP was prepared using prokaryotic expression system and was used to immunize New Zealand White rab-bits.Upon achieving the desired serum titer,total RNA was extracted from the splenocytes of rab-bits and reverse transcribed into cDNA.Using this cDNA as a template,degenerate primers were employed to amplify the genes of the rabbit antibody light chain variable region(VL)and heavy chain variable region(VH).The VL and VH regions were spliced together to form a complete scFv fragment via overlap extension PCR.The scFv was then ligated into the phagemid pComb3XSS and electroporated into competent E.coli TG1 cells to construct a rabbit-derived anti-NT-proCNP scFv immunological library.This library underwent four rounds of enrichment and screening to isolate specific single-chain antibodies.The selected antibody was subsequently ex-pressed in a soluble form within a prokaryotic system,and its immunological activity was evalua-ted.Using phage display technology,this study successfully identified a single-chain antibody scFv-1-CNP with strong antigen-binding activity and genetic sequence characteristics of scFvs,providing a research direction for further exploration of scFv applications in the detection of NT-proCNP.

The amino-terminal pro-C-type natriuretic peptide(NT-proCNP)is a diagnostic inflam-matory marker clinically used for diagnosing bacterial infections.This study aims to establish a phage display library of single-chain variable fragment(scFv)antibodies against canine NT-proC-NP and to screen for scFvs with high binding affinity to NT-proCNP.Initially,NT-proCNP was prepared using prokaryotic expression system and was used to immunize New Zealand White rab-bits.Upon achieving the desired serum titer,total RNA was extracted from the splenocytes of rab-bits and reverse transcribed into cDNA.Using this cDNA as a template,degenerate primers were employed to amplify the genes of the rabbit antibody light chain variable region(VL)and heavy chain variable region(VH).The VL and VH regions were spliced together to form a complete scFv fragment via overlap extension PCR.The scFv was then ligated into the phagemid pComb3XSS and electroporated into competent E.coli TG1 cells to construct a rabbit-derived anti-NT-proCNP scFv immunological library.This library underwent four rounds of enrichment and screening to isolate specific single-chain antibodies.The selected antibody was subsequently ex-pressed in a soluble form within a prokaryotic system,and its immunological activity was evalua-ted.Using phage display technology,this study successfully identified a single-chain antibody scFv-1-CNP with strong antigen-binding activity and genetic sequence characteristics of scFvs,providing a research direction for further exploration of scFv applications in the detection of NT-proCNP.

Antipyretic-analgesics are currently one of the most prescribed drugs in children.The clinical application of antipyretic-analgesics for children in our country still have irrational phenomenon, which affects the therapeutic effect and even poses hidden dangers to the safety of children.In this paper, suggestions were put forward from the indications, dosage form/route, dosage suitability, pathophysiological characteristics of children with individual differences and drug interactions in the symptomatic treatment of febrile children, so as to provide reference for the general pharmacists when conducting prescription review.

AIM:To investigate the effects of antioxidant N-acetylcysteine(NAC)on the lipopolysaccharide(LPS)-induced MAPK phosphorylation in mouse liver.METHODS:54 male mice were divided into three groups:control(n=6),0.9% sodium chloride 0.2 mL ip;LPS group(n=24):LPS 5 mg ip;NAC+LPS group(n=24):NAC 150 mg?kg-1?d-1 ip,for 3 d;LPS 5 mg ip after 1 h of NAC administration at 3rd day.The liver was excised with carbrital anesthesia after LPS or 0.9 % sodium chloride injection at 0.5 h,1 h,2 h and 6 h for GSH and MDA assays.The protein extracted from liver was assayed for the phosphorylation of MEK1/2,ERK1/2,p38 MAPK by Western blotting.TNF-? in liver was assayed by radioimmunoassay.RESULTS:MDA in the liver was decreased remarkably and the GSH in the liver was increased significantly by NAC pretreatment.The phosphorylation of MEK1/2,ERK1/2 and p38 MAPK in liver were inhibited significantly by NAC pretreatment after LPS challenge.Meanwhile,TNF-? in liver was decreased markedly.CONCLUSION:Reactive oxygen species plays a critical role in MAPK signaling during the LPS induced acute liver injury.NAC partially inhibits LPS-induced MAPK signaling by antioxidant effect and decreases TNF-? production.